Legal
Privacy policy
Last updated
Draft. This page has not yet had a final legal review and may change before HitaruJP launches in the app stores.
This policy explains what information HitaruJP (“we”, “us”) collects when you use the HitaruJP app on Android, iOS or the web, and the website at hitarujp.app. We’ve tried to write it plainly.
The short version
- We collect what we need to run your account and show you the right videos: your profile, what you’ve learned and what you’ve watched.
- We don’t sell your data, and we don’t show ads.
- When you ask for an AI explanation, the text you asked about is sent to Google’s Gemini model.
- You can ask us to delete everything at any time.
What we collect
Your account
You sign in with Google or with an email address and password. Sign-in is handled by Firebase Authentication, a Google service. Firebase stores your email address and sign-in details so you can log in.
Your profile and learning data
Stored in Google Cloud Firestore, linked to your account:
- Profile: display name, chosen character, JLPT level, why you’re learning and what content you’re interested in.
- Learning data: vocabulary you save, your flashcards and review history, study sessions, and the kana you’ve marked on the kana board.
Data our server keeps
Our own API (hosted on Render) keeps:
- a copy of your profile (as above), so we can recommend videos;
- the days you were active and how many times you opened the app;
- which catalogue videos you’ve watched;
- how many AI explanations you’ve requested, with the number of tokens used and an estimated cost, so we can keep the service running within budget.
Our server does not store your email address.
The website
The website (hitarujp.app) has no accounts or forms. If we use analytics, it is cookieless (no cookies, no personal data, no cross-site tracking) and only counts page views and button clicks.
How we use it
- To run your account and sync your progress between devices.
- To pick videos that match your level and interests.
- To generate AI explanations when you ask for them.
- To understand which features are used, fix problems and keep costs under control.
We don’t use your data for advertising, and we don’t sell it.
Who we share it with
We use these services to run HitaruJP. Each processes data only to provide its service to us:
| Service | What for | What it receives |
|---|---|---|
| Google Firebase (Authentication, Firestore) | Accounts and storing your learning data | Your sign-in details, profile and learning data |
| Google Gemini | AI explanations | The word, sentence or question you asked about |
| YouTube | Playing videos | YouTube’s embedded player may set its own cookies and collect data under Google’s privacy policy |
| Render | Hosting our API and website | Data passing through our server, as above |
We’ll also share information if the law requires it.
How long we keep it
We keep your data while your account exists. When you delete your account, we delete your profile and learning data from Firestore and our server within 30 days. Backups may take up to a further 30 days to expire.
Your rights
You can ask to see, correct, export or delete your data at any time. Email privacy@hitarujp.app from the address linked to your account. We’ll reply within 30 days. Depending on where you live (for example the EU, UK or California), you may have further rights under local law, including the right to complain to your data protection authority.
Children
HitaruJP is not intended for children under 13, and we don’t knowingly collect data from them. If you believe a child under 13 has created an account, contact us and we’ll delete it.
Security
Data is sent over encrypted connections (HTTPS) and stored with Google Cloud and Render, which encrypt data at rest. No system is perfectly secure, but we work to protect your information.
Changes
If we change this policy in a way that matters, we’ll update the date at the top and tell you in the app before the change applies.
Contact
Questions about privacy: privacy@hitarujp.app. Anything else: contact us.